1. Technical Field
The invention relates generally to material transport systems and, more particularly, to a cleaning system that removes residue from a conveyor and controls the generation of air-borne residue particles. Specifically, the invention relates to a material transport system having an air knife that impinges an air stream against a conveyor to remove the residue therefrom and a deflector to deflect the air stream and air-borne residue toward a chute or hopper after the air stream has impinged on the conveyor. The invention also relates to the removal of air-borne residue particles from the area surrounding the conveyor.
2. Background Information
Material transport systems are used primarily for transporting materials from one location to another. Material transport systems typically include a conveyor, which may be any of a variety of structures such as endless conveyor belts, chain belts and feeders, vibrating feeder beds, and foldable belts, as well as other devices of the type known and understood in the relevant art. Most notably, material transport systems include a material discharge chute for collecting and sorting material, which chute relates to the present invention.
When the materials transported by the conveyor are of a particulate nature, such as coal or breakfast cereal, the conveyor becomes coated with a residue of fine particles of the particulate material. The residue is produced by the breakage of the particulate materials, friction between the particulate materials and the conveyor, friction between the individual particles themselves, as well as other phenomena. When the particulate material is of a powdered consistency, such as powdered lime, the powdered material itself is the residue that becomes coated on the conveyor.
Such residue sticks to the conveyor as a result of phenomena such as static electricity or trace amounts of oil or water disposed on the conveyor or contained in the air, as well as due to other phenomena. The residue is continuously deposited on the conveyor as a result of conveying the particulate materials and ultimately results in fouling of the conveyor and failure of the material transport system if allowed to remain on the conveyor without cleaning. Moreover, the residue must be removed from the conveyor inasmuch as such residue contributes to an overall dusty environment that is unsafe, unsanitary, and unattractive.
The coating of residue on the conveyor has often proven difficult to reliably and safely remove. Specifically, brushes and scrapers that attempt to frictionally dislodge the residue from the conveyor often are only partly effective and moreover dramatically increase conveyor wear. The need thus exists for a device that removes the residue from a conveyor without increasing the wear of the conveyor.
The residue produced in transporting the particulate materials is typically both air-borne as well as coated on the conveyor. Such air-borne residue is preferably controlled in some fashion to prevent the air-borne residue from fouling the air surrounding the material transport system and settling on the floor, machinery, and other objects around the material transport system. As is understood in the relevant art, a head cover is typically disposed over the terminal end of the conveyor where the particulate materials are discharged into a chute for transfer onto another conveyor or into a packaging system. The head cover typically surrounds the terminal end of the conveyor and includes an evacuation system such as a dust vacuum that draws the air-borne residue away from the terminal end of the conveyor and into appropriate containers for disposal or reintroduction into the system. Such evacuation systems are, however, expensive to operate inasmuch as the disposal or reintroduction of the collected residue requires additional material handling and cost, and results in generation of additional air-borne residue.
Most evacuation systems in existing material transport systems are attached at the uppermost portion of the head cover, with the result that the evacuation system draws air-borne residue in a direction away from the flow of particulate material, thus preventing the air-borne residue from settling out of air suspension and back into the particulate material. While the air-borne residue must be captured for reasons of conveyor reliability, safety, and hygiene, such caption generates an expense that is preferably minimized.
The head cover typically includes a chute disposed at the lower end into which the particulate material is discharged. As the particulate material falls into the chute, the evacuation system removes the air-borne residue from inside the head cover for disposal.
The removal of residue from the conveyor can contribute to the presence of air-borne residue particles. An increase in the quantity of air-borne residue caused during cleaning of the conveyor thus results in increased evacuation requirements. The need thus exists for a device that reliably removes the residue from a conveyor without increasing the quantity of air-borne residue. Such a device preferably reduces the quantity of air-borne residue within the head cover.